Finding the Fourth Proportional to 1,128.43, 1,557.27 and 631.06

Step by Step Solution

1. Step 1: Write the proportion equation
   1,128.43 : 1,557.27 = 631.06 : x
2. Step 2: Convert to fraction form
   1,128.43/1,557.27 = 631.06/x
3. Step 3: Cross multiply
   1,128.43x = 1,557.27 × 631.06
4. Step 4: Simplify right side
   1,128.43x = 982,729.75
5. Step 5: Solve for x
   x = 982,729.75/1,128.43
6. Step 6: Final answer
   x = 870.88